question

mysik avatar image
mysik asked

VE.Direct diy self made cables or buying cheap ones on eBay, Alibaba, Amazon.

Hi.

Can I use JST-PH plugs to make VE.Direct to VE.Direct cable? Just simply connect ground to ground, 5v to 5v and Tx to Rx (cross cable)??? Will it work like that???

This is required to connect BMV712 to VenusGX

Kind Regards

VE.Directwiringdiy
vedirect.png (4.2 KiB)
vedirect.png (3.3 KiB)
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7 Answers
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

I have to make a warning for anyone else reading this: I’m fiercely against self making of cables.


dont make rj45 cables yourself, dont make vedirect cables yourself, and dont make your own usb interfaces either by buying low cost usb cables on ebay, amazon or alibaba.

The reason is that already many times we’ve spent a lot of valuable r&d time looking into strange issues reported by customers, to in the end find our that there was a self made cable with an issue in it.

For example; first it worked with the self made cable, then a firmware update was done. Then it didnt work anymore: “ooh the firmware update broke my system!!”. But after many hours, there was no bug, but communication requirements changed slightly in the firmware, (requiring both rx and tx for example, instead of only one of them), and caused the self-made cable to cause trouble.

Its simply utterly frustrating to see our r&d time be wasted on that.

I have seen low cost usb cables with only rx working (tx & rx is needed) and also seen cables that after a while start to generate false data, or lose bits & bytes, and so forth.

Ofcourse I understand the price barrier for a genuine cable, and I know people will use self made cables anyway; and I know it works well often. - but when you do use those - please don’t ask anyone for help in case of issues (however seemingly unrelated!).

Instead get a known good cable first.


I hope to never hear about self-made cables costing valuable support time again.


End-of-rant ;o)


(updated with more details on 2020-6-30)

2 comments
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basti avatar image basti commented ·

I would love to by the original Victron cable, but the plug ist too bulky to connect to one of my items in my installation (SmartShunt 500 has the connector on its side, and therefor would require much more space if the Victron cable is used). If I buy the standard JST PH 4Pin 2.0mm connectors, I have a much smaller footprint. Granted: I also have less/no shielding and there might or might not arise issues from that...

If you guys would have a VE-Direct vable with a 90° connector, I would be sold. Do you?

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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ basti commented ·

Hi Basti, I thought so, yes - see pricelist on our website. Good evening

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Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @Mysik


Update!!

I previously wrote that the cables are straight, this was incorrect, cable is crossed indeed!



3 comments
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mysik avatar image mysik commented ·

I've done straight cable as instructed and it is working fine. Thx

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hummingbear avatar image hummingbear mysik commented ·

@Mysik for USB A which pins would VE.Direct RX and TX be assigned to?VE Direct is also fine with 5V yes?
1611790592257.png

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1611790592257.png (141.5 KiB)
raul avatar image raul commented ·

I installed a new Victron system in my caravan last weekend. Because of the very limited space I had to build VE.Direct cables myself. I built two straight wired cables according to documentation. The connected SmartShunt 500A worked immediately. Next I connected a SmartSolar Charger MPPT 100/50 which was not recognized by the Cerbo GX. I assumed I made a mistake and so I built a new cable. This did not work either. I was very frustrated because changing the cables and ports on the Cerbo GX did not work. Today, for fun, I tried a crossover cable and my SmartSolar Charger was recognized.


Why do you need a crossover cable for the SmartSolar Charger and a straight one for the Smart Shunt?

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marky01 avatar image
marky01 answered ·

@mvader (Victron Energy) As a network engineer I totally understand your frustration regarding very valuable time spent troubleshooting other peoples crap cabling, perhaps the issue is one that Victron can take head on in some way.

I have been looking at buying a Multiplus 2 GX with Pylon Batteries and a 250/70 MPPT and the thing that is getting to me is that no cables come with the equipment, for example if I want to update firmware, ok thats another £?? for the MK3, I want to connect the multi to another device ok thats another £?? for a VE direct cable or a CAN cable.

I know this is a difficult task, with so many scenarios but is there any business model where cables for certain standard connections be included with some devices i.e. if I want to use a meter in an ESS setup could the 485 to USB come with the meter ?


Regards

Mark


2 comments
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Hi @Marky01

Most Victron systems are still installed by installers that do many systems, adding those cables would be a big waste as most will be unused. For end-user installs, a dealer can also update the firmware before sending out the unit.

(also, on a 3 phase system you'd only need one MK3 cable)

On the energy meters: there are multiple options to connect: different cable length, wireless, etc.


CANbus cables: the same, Victron equipment uses standard 'straight' RJ45 cables, but some other brands (Pylontech, BYD, ??) use a different pinout, therefore needing different cables.

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marky01 avatar image marky01 Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

@Daniël Boekel (Victron Energy Staff) Thank you for the reply. I see your point and I suppose if you want quality products you do have to pay a little more.

Regards

Mark

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raul avatar image
raul answered ·

Today I received my ordered original Victron VE.Direct cable. The measuring confirmed that the original cables are crossed and not straight wired as described in the "VE.Direct-Protocol" documentation.

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raul avatar image
raul answered ·

Currently I have two components connected to the Cerbo via VE.Direct.

As already described, the MPPT 100/50 solar charger runs only with a crossed VE.Direct cable. The 500A SmartShunt runs since the installation with a straight VE.Direct cable.

Last week I tried to upgrade from firmware v2.60 to the latest firmware v2.62, but after the upgrade the SmarShunt is no longer recognized by the Cerbo. After the downgrade to the v2.60 it was displayed again in the overview.

As soon as I have time I exchange the VE.Direct cable (straight connected) from the SmartShunt against a crossed one and see if the new firmware recognizes the SmartShunt.

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raul avatar image
raul answered ·

Hi,

yesterday I crossed the VE.Direct cable from the SmartShunt to the Cerbo and then I was able to perform the firmware update to v2.63 without losing the connection to the SmartShunt.

Again briefly summarized.

The original Victron VE.Direct cables are crossed. With the firmware v2.60 partially (for example with the SmartShunt) straight VE.Direct cables worked. From firmware V2.61 only crossed VE.Direct cables work. The information in the document "VE.Direct Protocol" in the current version 3.30 in the section "Physical interface" is wrong.


Self built VE.Direct cables must be crossed as shown in the first post.

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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ commented ·

Hi where in our documentation do we say that cables are straight?

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raul avatar image raul mvader (Victron Energy) ♦♦ commented ·

Hi.

On the page "https://www.victronenergy.com/support-and-downloads/technical-information" you can download the file "VE.Direct Protocol".

On the second page it says that for a producer RX is on pin 2 and TX on pin 3 but for a consumer RX is on pin 3 and TX on pin 2.


vedirect-documentation.png


For a communication, as far as I know, TX must be wired to RX.vedirect-connection.png

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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ raul commented ·

Hi @Raul, ok thank you. we'll check to more clearly note it in the document.

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tmo avatar image tmo raul commented ·

More confusion (?):

If you look at the manual for the MTTPs with load output (BlueSolar) (the figures for the VE.Direct-port) and then on the VictronConnect spesific document for MTTPs (4.2 and 4.5: 2.Load output config., the TX must be pin 2 and RX pin 3.

This assumes that an TX always is defined as an output from a unit and a RX always is an input: I find it simplest to always use this definision for the VE.Direct port !

(Ref. the confusion that can arise in the RS232-definision where they can be both dependent of the units role).


Nice with Victrons open policy. Keep that !

Regards

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gro avatar image
gro answered ·

We have not always run with Rx and Tx crossed over in our cables. Back in the day, we had Data Terminal Equipment (DTE) and Data Communications Equipment (DCE). Between straight cables with Tx to Tx and Rx to Rx where common place. Tx pin was not always a source of data. A DCE received the data to be transmitted out to the network on its Tx pin, e.g. a modem. So I can see that unless equipment is declared as either a DTE or DCE there is potential for confusion. Most people appear to treat all equipment as DTEs therefore expect the use of crossed TX/Rx cables.

Still not a reason for documentation to be incorrect , but perhaps for people to expect all data cables to be crossed.


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